<!DOCTYPE html>
<html>
<head>
	<title></title>
	<style type="text/css">
		canvas{
			border: 1px solid #333;
		}
	</style>
</head>
<body>
	<canvas width="600" height="400" id="canvas"></canvas>
	<script type="text/javascript">
		//相当于拿到一张纸
		var canvas=document.getElementById("canvas");
		//获取画笔
		var ctx=canvas.getContext("2d");
		var R=150

		//移动坐标系
		ctx.translate(300,200)

		//绘制大圆
		ctx.beginPath()
		ctx.lineWidth=5
		ctx.arc(0,0,R,Math.PI*2,false)
		ctx.stroke()


		//绘制分针辐射线
		

		for(var i=0;i<60;i++){
			ctx.save()
			ctx.rotate(6*Math.PI/180)
				ctx.beginPath()
				ctx.lineWidth=2;

				ctx.moveTo(0,0)
				ctx.lineTo(0,-R)
				ctx.stroke()
			// ctx.restore()
		}
		

	





	</script>
</body>
</html>
